Characteristic toxicity of daxorubicin -

Ans. is 'b' i.e., Cardiotoxicity Anthracvclineso Anthracyclines are anticancer antibiotics and they include Doxorubicin (Adriamycin) and Daunorubicin.o The major toxicity of anthracyclines is potentially irreversible cumulative dose related toxicityo They may causes arrhythmias and cardiomyopathy. Because of their carditoxicity these drugs should be avoided in the patient with MI and CHF.o The antracyclines exert their anticancer activity through four major mechanisms -1. Inhibition of topoisomerase II2. Blockade of synthesis of DNA & RNA, and DNA strand scission.3. Alter fluidity and ion transport.4. Generation of semiquinone free radicals and oxygen free radicals - this free radical mechanism is the cause of cardiotoxicity.o This cardiootoxicity can be prevented by using dexrazoxane (a free radical scavenger) and a-tocopherol.o Liposomal forms of these drugs also reduce cardiac toxicity.o Adverse effects - Dose related myelosuppression with neutropenia, dose limiting mucositis, cardiotoxicity (AI 96, 94, AIIMS 93)o Uses of Doxorubicin# Ca Breast# Ca Endometrium# Ca ovary# Ca testicle# Ca thyroid# Ca lung# Hodgkin s disease# Non Hodgkin disease# Sarcomaso Uses of Daunorubicin# It has far narrower spectrum of activity than Doxorubicin# It is mainly used in acute leukemia.